Why brake test is performed on DC shunt motor?

Why brake test is performed on DC shunt motor?

In Direct Method, the DC machine is subjected to rated load and the entire output power is wasted. The ratio of output power to the input power gives the Efficiency of DC Machine. For a DC Generator the output power is wasted in resistor. Direct Method of testing when conducted on a motor is also known as Brake Test.

What is a brake test on dc series motor?

In the brake test, the dc machine is tested by actual loading with the help of breaks. Since the load is applied directly to the machine shaft, it is a direct method of testing a dc machine.

What is the purpose of brake test?

A brake test is a deceleration test carried out between two speeds. Data taken during the test is used to calculate the time taken and distance travelled. A trigger can be used to measure the point of activation of the brake pedal.

How do you test a DC shunt motor?

first test the field winding with a megohmmeter to check, that the winding has no short to the housing. Then check the current consumption of the field winding. If you can, start with a low voltage and rise it until you reach the nominal voltage. Look for the maximum current at the specification plate.

Why the starting torque is low in DC shunt motor?

The high number of turns allows a strong magnetic field to be generated, but the smaller gauge wires provide a high resistance and limit the current flowing through the shunt coil. Therefore, the starting torque of a DC shunt motor is low, meaning that the shaft load must be small at startup.

Where is DC shunt motor used?

The applications of shunt DC motor include the following. These motors are used wherever stable speed is required. This kind of DC motor can be used in Centrifugal Pumps, Lifts, Weaving Machine, Lathe Machines, Blowers, Fans, Conveyors, Spinning machines, etc.

What is the application of DC shunt motor?

How do you perform a brake test?

STEP 1: Before starting the engine, depress the brake pedal fully. The brake boost light should come on and the pedal should stiffen about halfway down. You should hear the electric motor kick in with a low pitch whine. STEP 2: With your foot over the brake pedal, turn the key to the on position.

How to conduct brake test on DC series motor?

For conducting Brake Test on DC Series Motor, it must be ensured that belt is sufficiently tight before the motor is switched on to the sully as DC Series Motor shall not be started at no load. 1) The Spring Balance Readings are not stable rather it fluctuates.

How is the brake band fixed on a shunt motor?

The brake band is fixed with the help of wooden blocks gripping the pulley. The sample brake test described above can be used for small motors only. Because in the case of large motors.

How big is a d.c.shunt motor?

Example 31.2 (b). In a brake-test, on a d.c. shunt motor, the tensions on the two sides of the brake were 2.9 kg and 0.17 kg. Radius of the pulley was 7 cm. Input current was 2 amp at 230 volts.

How is a brake applied on a D.C machine?

For this purpose, two simple methods can be used. In this Brake test on D.C Machines, a brake is applied to a water-cooled pulley mounted on the motor shaft as shown in Fig. (6.1). One end of the rope is fixed to the floor via a spring balance S and a known mass is suspended at the other end.